Lubricating oil compositions



United States Patent LUBRICATING OIL COMPOSITIONS Forrest J. Watson andRupert C. Morris, Berkeley, and John L. Van Winlrle, San Lorenzo,-Calif., assignors to Shell Development Company, New York, N. Y., acorporation of Delaware No Drawing. Application August 17,v 1956Serial'No. 604,618

7 Claims. (Cl. 252--32.5)

This invention relates to lubricants, and particularly to lubricatingcompositions which are suitable. for use in equipment operating underextreme conditions, such as under extreme pressure, variable speed andwide temperature conditions.

It has been observed that certain types of phosphorus acids as definedmore specifically hereinafter, impart outstanding extreme pressureproperties to various lubricating compositions. However, these veryeffective agents are in general undesirable because they promote wearand cause corrosion.

The phosphorus acids referred to can be represented by the generalformula:

Rl"(OH)z (I) wherein R is a polyhalohydrocarbyl radicaltand preferably aperchloroalkyl radical.

The art discloses that some of the undesirable properties of these acidscan be overcome by forming secondary amine salts of thesepolyhalohydrocarbyl. phosphonic acids such as the di(2-ethyl-hexyl)aminesalts of butyl trichloromethylphosphonic acid. However, in many casesthese amine salts lack desired oil solubility and in storage tend toprecipitate from the oil and form sludge.

It has now been discovered that certain amine salts of monochloroalkylphosphonic acids, the. acid being represented by the formula:

RP(OH)2 (II) wherein R is a monochloroalkyl radical of from 1 to 4 andpreferably 1 to 2 carbon atoms and the chlorine atom is in the alphaposition relative to the phosphorus atom, possess outstanding extremepressure and load carrying properties, have good oil solubility and arenon-corrosive and non-staining when in contact with ferrous ornonferrous metals.

. 2,874,120 Patented Feb. .17, 1959 v ce chloroalkyl phosphonic acidsare highly branched aliphatic primary amines or aliphatic secondaryamines of at least 8 carbon atoms. Of thev highly branched aliphaticprimary amines, the tertiary alkyl primary amines are preferred and theycan be prepared by any suitable means such as described in the U. S.Office of the Publication Board Report No. 88843. Other highly branchedprimary amines can be prepared by converting primary branched chainolefins as fully described by P. W. Sherwood in the Oil and Gas Journal,June 9, 1949, page 71, and in the February 1953 issue of PetroleumProcessing, to the corresponding nitriles and converting the nitrile tothe amine by catalytic hydrogenation. Another method is to converthighly branched alcohols to the corresponding halides and to form theamines derived from the halide in the customary manner such as byreacting with ammonia.

It has been found that the tertiary alkyl primary amines, containing asthe tertiary alkyl radical, the'radical' of polyisobutylene,polypropylene and mixtures thereof are particularly effective for thepresent purpose and they constitute a preferred class of amines for thepractice of the invention. Accordingly, 1,I,3,3-tetramethylbutylamine(from the amination of diisobutylene), 1,1,3,3,5,5-hexamethylhexylamine(from triisobutylene), l,1,3,3,5,5,7,7- octamethyloctylamine (fromtetraisobutylene) and 1,1,3, 3,5,5,7,7,9,9-decamethyldecylamine (frompentaisobutylene) are specific preferredamines, which are suitably usedindividually or as mixtures thereof. In addition to these tertiaryalkyl' primary amines, tertiaryalkylmethyl primary amines, such as2,2,4,4-tetramethylpentylamine, 2,4,4,6,o-hexamethylheptylamine and thelike are suitable.

Other tertiary alkyl primary amines which can beused include the C andhigher amines of this type mentioned in U. S. Patents 2,160,058,2,606,923 and 2,611,782, such as tert-tridecylamine CzHt as well asisoheptyldiethylcarbinylamine, isooctylethylpropylcarbinylamine, and thelike. Primary amines of this type are commercially available from Rohmand Haas Company under the trade name of Primenes, specific productsbeing Primene 81-R, which is a mixture of primary alkylamines containingfrom about 12 to 15 carbon atoms and Primene J M-T, which is a similartertiary alkylamine mixture containing an average of about 18 to 24carbon atoms.

The following arethe properties of some amines which can be used to formthe amine salts for use in lubricating compositions of this invention.

Table 1.Pr0perties Tertiary-octylamine Alkylamine 81-R Alkylamine J M-[A1 A3 Formula t-CiH NH Principally t-C12H25NII2 to PrincipallytCisHavNHr to F015 31 2. J CuHuN 2. Molecular weight 128 Principally185-227 Principally 269-353. Average molecular weight- 19 315 1.45s;570% at 265-308" 0. (760 mm).

The acid portion used to make either the partial or full amine salt canbe prepared by the method described by Barnard et al. in the CanadianJournal of Chemistry,

The amines which form effective salts-of-the mono- The secondary amineswhich can beused to form effective salts of the phosphorus acids arepreferably those aliphatic and cycloaliphatic amines which contain from10 to 36 carbon atoms. Illustrative of such amines are diamylamine,dihexylamine, di(2-ethylhexyl) amine, dioctylamine, didecylamine,didodecylamine,-- ditetradecylamine, dihexadecylamine, dioctadecylamine,dibromodioctadecylamine, isopropyloleylamine, diricinoleylamine,butylricinoleylarniria butyl 2 ethylhexylamine, dilauryl- OI-LA (III)and I o OH.A Rl

OILA (1v) wherein R is the same as defined in Formula II, and A is along-chain highly branched aliphatic primary amine -or aliphaticsecondary amine, having at least 8 carbon atoms and higher such as up to30 carbon atoms in the molecule.

The amine salts of the monochloroalkyl phosphonic acids and mixturesthereof as described can be prepared by interacting the selected aminewith monochloroalkylphosphonic acid in a suitable solvent if desired andunder suitable conditions such as mixing at elevated temperature,stirring and heating. Salts produced in the foregoing or equivalentmanner can be purified by re crystallization from suitable solvents orother means which will be apparent to those skilled in the art. Forexample, monochloromethylphosphonic acid was reacted at a temperature ofaround 100 C. with a mixture of t'CmHgqNHz t0 t'C24H49-NH2 in an amountsufiicient ot neutralize the total acidity of the acid, namely, one moleof the acid for two moles of the amine. Theprod uct is represented bythe formula 0 Ol-LA: Clem-i OH.A:

or equivalently T 010 Hr- P OH. Al

or equivalently Another excellent non-corrosive extreme pressureadditive having good oil solubility was prepared by using only half thestoichiometric amount of amine (A required to neutralize the totalacidity of monochloromethanephosphonic acid. The product had the formulaor equivalently The partially neutralized highly-branched-chain primaryamine salts which are specifically preferred include: t'C1 H25NH t-C HNH to t-C15H31NH, t'C1 H3NH to t-C .;H NH dimethylneopentylcarbinylamine, tert. tridecyl amine salts of monochloromethyl phosphonic acid,mono-alpha-chloroethylphosphonic acid.

The secondary amine salts which are specifically preferred include:di-2-ethylhexylamine, .di-1'isobutyl-3- methylbutylamine, didecylamine,dioctadecylamine, isopropyloleylamine, butyl-Z-ethylhexylamine,dicyclohexylamine salts of monochloromethylphosphonic acidmonoalpha-chloroethylphosphonic acid.

The amine salts of the monochloroalkylphosphonic acids can be used inamounts ranging from about 0.01% to about 10% and preferably between0.1% and 5% by weight.

Base oils to which agents of this invention are added may be selectedfrom a variety of natural oils such as paraffinic, naphthenic and mixedbase mineral oils having a viscosity range such as from 50 SUS at R, upto 250 SUS at 210 F. In addition, synthetic oils may be used such aspolymerized olefins, alkylated aromatics, polyalkyl silicone polymers,e. g., liquid dimethyl silicone polymer, other silicone polymers, HS-adducts of unsaturated ethers and thioethers, e. g. H 8 adduct ofdialkyl ether, esters, e. g., di(2-ethylhexyl)sebacate. Mixtures ofnatural and synthetic oils can be used.

The outstanding properties which compositions of this invention possessis evidenced from the data presented in Table II. The L-13 rust test isdescribed in the 1946 CRC Handbook published by the Co-OrdinationResearch Council; the four-ball test is described in Engineering, vol.136, July 13, 1933; the bearing stain test consists of immersing a smallclean Timken bearing in the composition being tested and heating thecomposition to C. for 65 hours. The bearing is removed, solvent washedand staining (10=bearing stain and 0=clean) observed in the cup and coneof the bearing. The reverse hypoid score load in H. P. is measured onthe hypoid gear machine operated at 4000 R. P. M., giving resultssimilar to the L-l9 test described in the CRC Handbook mentioned above.

T able ll SULFURIZED PALE OIL BASE ADDITIVE PRESENT IN AMOUNT OF 0.12% PSalt of amine A" of Table I 221-251 and monochloromcthyl phosphonicacid.

PALE OIL BASE SUS AT 100 F., PRESENT IN AMOUNT OF 0.12% 1 Salt 1 ofamine A oi Table I 224-250 and monochloromethyl phosphonic acid.

Salt 2 of amine A of Table I andmonochloromethyl phos- 178-200 phonicacid. None 56- 63 DI-2-ETHYL HEXYL SEBAOATE BASE ADDITIVE PRESENT IN ANAMOUNT OF 0.12% P Salt 1 of amine A of Table I andmonochloromethyl phos-200-224 phonic acid. None- 40- 45 1 Total acid neutralized.

3 Strong acidity neutralized only.

i Dibutyl derivative of polyoxypropyicne glycol having a viscosity of 1%Bus at 100 F.

In addition to the additives already described, lubricating oilcompositions contemplated herein may contain other agents, such aspour-point depressants, oiliness agents, blooming agents, compounds forenhancing the viscosity index of the lubricating oil, peptizing agents,metal deactivators, etc.

We claim as our invention:

1. A lubricating oil composition comprising a major amount of a minerallubricating oil and from about 0.01% to about by weight of anoil-soluble aliphatic amine salt of a monochloroalkylphosphonic acidcontaining from 1 to 4 carbon atoms in the alkyl group and wherein thechlorine atom is on the alpha carbon to the phosphorus atom, the amineportion of the salt being a branched-chain-aliphatic amine having from'8 to 24 carbon atoms and selected from the group consisting of primaryand secondary amines,

2. A lubricating oil composition comprising a major amount of minerallubricating oil and from about 0.01% to about 110% by weight of an oilsoluble branched-chain- C -aliphatic primary amine salt of monochloro Calkyl phosphonic acid wherein the chlorine is on the alpha carbon to thephosphorus atom.

3. A lubricating oil composition comprising a major amount of minerallubricating oil and from about 0.01% to about 10% by weight of an oilsoluble branched-chain- C -aliphatic secondary amine salt of monochloroC alkyl phosphonic acid wherein the chlorine is on the alpha carbon tothe phosphorus atom. t

4. A lubricating oil composition comprising a major amount of minerallubricating oil and from about 0.1 to about 5% by weight ofdi-2-ethylhexylamine salt of monochloromethylphosphonic acid.

5. A lubricating oil composition comprising a major amount of minerallubricating oil and from about 0.1 to about 5% by weight of a mixture oft-C H NH to t-C H NH amine salt of monochloromethylphosphonic acid.

6. A lubricating oil composition comprising a major amount of minerallubricating oil and from about 0.1 to about 5% by weight of a mixture oft-C H NH to C H NH amine salt of monochloromethylphosphonic acid.

7. A lubricating composition according to claim 1, wherein themonochloroalkylphosphonic acid is alphachloroethylphosphonic acid.

References Cited in the file of this patent UNITED STATES PATENTS2,169,185 Shoemaker Aug. 8, 1939 2,683,691 Thorpe July 13, 1954 2 1 Wi m-,---e---.-.----r-- an- 1 7

1. A LUBRICATING OIL COMPOSITION A MAJOR AMOUNT OF A MINERAL LUBRICATINGOIL AND FROM ABOUT 0.01% TO ABOUT 10% BY WEIGHT OF AN OIL-SOLUBLEALIPHATIC AMINE SALT OF A MONOCHLORALKYPHOSPHONIC ACID CONTAINING FROM 1TO 4 CARBON ATOMS IN THE ALKYL GROUP AND WHEREIN THE CHLORINE ATOM IS ONTHE ALPHA CARBON TO THE PHOSPHOROUS ATOM, THE AMINE PORTION OF THE SALTBEING A BRANCHED-CHAIN-ALIPHATIC AMINE HAVING FROM 8 TO 24 CARBON ATOMSAND SELECTED FROM THE GROUP CONSISTING OF PRIMARY AND SECONDARY AMINES.